Plate for heat exchange arrangement and heat exchange arrangement

Abstract

A plate for a heat exchange arrangement for the exchange of heat between a first and a second medium. The plate has a first heat transferring surface in contact with the first medium and a second heat transferring surface in contact with the second medium. The plate includes an inlet porthole for the first medium; an inlet porthole for the second medium, and an outlet porthole for the first medium. The first heat transferring surface includes a protrusion forming at least one ridge arranged to divide the heat transfer surface into at least a first region in direct thermal contact with the inlet porthole for the second medium, and a second region not in direct thermal contact with the inlet porthole for the second medium. The second region substantially surrounds the first region. The inlet porthole for the first medium is arranged in the first region, while the outlet porthole for the first medium is arranged in the second region. Moreover, the at least one ridge forms at least one elongated transfer channel arranged to convey the first medium from the first region to the second region.

Description

TECHNICAL FIELD[0001]The present invention relates to plate for a heat exchange arrangement and a heat exchange arrangement for the exchange of heat between a first and a second medium.BACKGROUND OF THE INVENTION[0002]Plates and heat exchange arrangements of the above-mentioned type are used to e.g. heat up tap water “on-demand” without storage tanks by combustion of fuel, typically gas. The water is then heated from about 20° C. to about 60° C. The gas is at the same time cooled by the tap water, i.e. the tap water is heated by the gas. Combustion gases must be cooled from about 1500° C. to as low temperature as possible. Condensation provides additional thermal energy from the fuel due to the release of latent heat. Water vapour from the combustion gases condenses when in contact with low temperature metal surfaces of the heat exchange arrangement. The temperature of the metal surfaces varies along the heat exchange arrangement and it is determined by the temperature and flow char...

AI Technical Summary

Benefits of technology

The invention provides a heat exchange arrangement for gas-fired hot water heaters and burners that includes a unique plate design. This design allows for optimal heat transfer and higher energy efficiency while also reducing the risk of thermal fatigue and leakage. The combustion gas inlet region is particularly critical and the heat exchange arrangement helps to keep the metal surfaces at acceptable levels for product reliability. Additionally, the heat exchange arrangement helps to achieve efficient condensation by integrated cooling of the burning chamber and the medium used for heating the other medium. Overall, the invention provides a compact design and improved performance for gas-fired hot water heaters and burners.

Problems solved by technology

Thermal problems have previously prevented use of cost effective and compact heat exchange arrangements in particularly gas-fired hot water heaters and burners.

This can cause thermal stresses and leakage.

High metal temperatures lead to high water temperatures, which in turn lead to boiling risk and thus, risk for mechanical damage of the heat exchange arrangement.

Other risks are scaling, fouling (precipitates from water that attach to the metal surface), causing danger of decreasing water cooling capacity and thus, the presence of a positive feedback loop towards higher metal temperatures over time.

High metal temperatures also lead to high thermal stresses in the metal, which in turn can lead to formation of cracks and thus, failure (leakage) of the product.

Prior art plates for heat exchange arrangements and heat exchange arrangements such as those described and illustrated in e.g. US 2001 / 0006103 A1, EP 1700079 B1 and EP 2412950 A1, are not capable of solving the above-mentioned drawbacks and problems in a satisfactory manner.

Using such an external channel, this design provides advantageous cooling of an end piece of the heat exchanger, but is on the other hand less efficient and more complex than the solution presented herein.

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